WEEK 8 - SAMPLING

Question 1

What does participant mean?

Answer 1

someone chosen to take part in a study

Question 2

What is the theoretical population (or target population)

Answer 2

The larger group that the researcher wants to generalise their findings to

Question 3

What is the study population (or accessible population)

Answer 3

Is the population that the researcher has access to draw participants from

Question 4

What is a sampling frame

Answer 4

is a detailed list of all participants, which can include people, locations or events in a population.

Question 5

What is a sample?

Answer 5

is the group of participants who have been chosen to be a part of the current study

Question 6

What is sampling?

Answer 6

the process of selecting participants, so that researchers can attempt to generalise their results back to a theoretical population.

Question 7

What are the types of sampling?

Answer 7

• Probability sampling
• Non-probability sampling

Question 8

What type of sampling in quantitative

Answer 8

• In quantitative research (aim is to recruit a sample that is representative of the theoretical population to permit generalisation) = probability samples

Question 9

What type of sampling in qualitiative?

Answer 9

• In qualitivate research (aim to tare individual cases that are data rich) = non-probability samples

Question 10

Probability Sampling approaches

Answer 10

• simple random
• systematic random
• strafed random
• cluster
• multi-stage

Question 11

Non-Probability Sampling approaches

Answer 11

• convenience
• snowball
  -quota
• purposive

Question 12

What is Sampling error?

Answer 12

• Measurement error refers to errors that take place with the data, whereas sampling error occurs when the group of participants chosen (the sample) is inadequate or not random enough

Question 13

What are the two types of sampling errors?

Answer 13

• random errors
• systematic errors
• both can introduce bias

Question 14

What are random errors?

Answer 14

• Random errors are common
• Occur randomly in a sample as a result of under‐ or over representation of certain groups.
  -Likelihood of random errors can usually be reduced by increasing the sample size

Question 15

What are systematic errors?

Answer 15

• Systematic errors usually occur as a result of inconsistencies or errors in the sampling frame
  Researchers should take care when designing the sampling frame

Question 16

Power of the Study

Answer 16

• Most studies will use 80% power, which means they will have an 80% probability of detecting a real difference if it exists. This means there will be a 20% probability of not detecting a real difference
• If a power calculation is not conducted, confidence in the findings is reduced because it is unknown whether the sample was too small to detect differences that exist or may detect differences that, in fact, do not exist in the population

Question 17

What is Statically signitifcanr effect

Answer 17

The significance of research findings relates to the probability of detecting a statistically significant effect or difference between study groups in the sample when it does not exist in the target population

Question 18

Probability — Type I Error

Answer 18

• If an event is impossible, then its probability is 0. If an event is certain, its probability is 1.
• researchers will say that the intervention works or that a real difference between groups exists when it does not

Question 19

the significance (α) level

Answer 19

• If the α level is set at 5%, a significant result means that we can be 95% confident that a real difference exists in the population and there is a 5% probability that the finding was due to chance alone
• clinical trials of medicines or interventions, the α level can be set more stringently at 1% (a 1% probability that the finding was due to chance alone)

Question 20

type II (β) error

Answer 20

• the probability of finding that there is no effect or difference between groups in the sample when, in the population, there is a true effect or difference

Question 21

What is Statistical ‘power’

Answer 21

• is used to describe the probability of detecting a real difference that exists in the population
• required sample size can be calculated using a power analysis

Question 22

Power Analysis

Answer 22

• requires some information about the expected range of scores (variance or standard deviation) that would be expected within the population being studied

Question 22

Sampling in Qualitative Research

Answer 22

• The literature sometimes suggests a range or a minimum and maximum number of participants or cases for qualitative research to be valid
• Ranges depend considerably on the type of topic that is being studied and other factors (e.g. the nature of the research questions, the homogeneity or heterogeneity of the population)

Question 23

What is Heterogeneity

Answer 23

looks at how diverse the results are for studies in a review

Question 24

What is a confidence interval?